The kidney is an important organ that functions to keep physical health, by which waste products, such as harmful or detrimental substances generated as a result of metabolic activity within a living organism, are removed from the blood by filtration.
An example of kidney disorders is kidney failure, and a therapeutic method therefor is artificial dialysis, for example. However, the burden imposed by medical expenses required for the therapeutic method is high, and thus the kidney failure is still a world-wide problem, not only from medical aspect, but also from medical economic aspect. Another example of a therapeutic method for kidney failure is renal transplantation, but in Japan especially, shortage of donor organs is severe.
Meanwhile, pluripotent cells such as embryonic stem cells (ES cells) and induced pluripotent stem cells (iPS cells), which can be obtained via introduction of an undifferentiated cell-specific gene(s) into somatic cells, have been reported (U.S. Pat. No. 5,843,780 or WO 2007/069666). Therefore, as a therapeutic method for kidney failure, a therapeutic method that involves transplanting renal cells obtained by inducing differentiation of these pluripotent stem cells has been investigated. Moreover, developing therapeutic agents using homogeneous renal cells from these pluripotent stem cells is also under consideration.
The mammalian kidney is formed through three stages consisting of pronephros, mesonephros, and metanephros. Among these stages, the metanephros is known to be generated in the posterior region of the intermediate mesoderm.
In this context, although a method for inducing differentiation of mouse pluripotent stem cells into intermediate mesoderm for nephrogenesis has been investigated (Mae S, et al. (2010), Biochem Biophys Res Commun. 393: 877-882), to date, the efficient induction of the differentiation of human pluripotent stem cells into intermediate mesoderm has never been reported.